Fully Kinetic Simulations of Proton-Beam-Driven Instabilities from Parker Solar Probe Observations

Abstract

The expanding solar wind plasma ubiquitously exhibits anisotropic non-thermal particle velocity distributions. Typically, proton Velocity Distribution Functions (VDFs) show the presence of a core and a field-aligned beam. Novel observations made by Parker Solar Probe (PSP) in the innermost heliosphere have revealed new complex features in the proton VDFs, namely anisotropic beams that sometimes experience perpendicular diffusion. In this study, we use a 2.5D fully kinetic simulation to investigate the stability of proton VDFs with anisotropic beams observed by PSP. Our setup consists of a core and an anisotropic beam populations that drift with respect to each other. This configuration triggers a proton-beam instability from which nearly parallel fast magnetosonic modes develop. Our results demonstrate that before this instability reaches saturation, the waves resonantly interact with the beam protons, causing perpendicular heating at the expense of the parallel temperature.

References in corpus (15)

• Ion Scale Electromagnetic Waves in the Inner Heliosphere
• Parker Solar Probe observations of proton beams simultaneous with ion-scale waves
• The In Situ Signature of Cyclotron Resonant Heating
• Inferred Linear Stability of Parker Solar Probe Observations using One- and Two-Component Proton Distributions
• Ensemble Simulations of Proton Heating in the Solar Wind via Turbulence and Ion Cyclotron Resonance
• Strong perpendicular velocity-space in proton beams observed by Parker Solar Probe
• On the role of solar wind expansion as a source of whistler waves: scattering of suprathermal electrons and heat flux regulation in the inner heliosphere
• Spectral properties and energy transfer at kinetic scales in collisionless plasma turbulence
• Modeling ion beams, kinetic instabilities, and waves observed by the Parker Solar Probe near perihelia
• Linear Stability in the Inner Heliosphere: Helios Reëvaluated
• Ion-Driven Instabilities in the Inner Heliosphere I: Statistical Trends
• Electromagnetic Ion-Ion Instabilities in Space Plasmas: Effects of Suprathermal Populations
• Conditions for proton temperature anisotropy to drive instabilities in the solar wind
• Large Scale Linear Magnetic Holes with Magnetic Mirror Properties in Hybrid Simulations of Solar Wind Turbulence
• Mixing the solar wind proton and electron scales. Theory and 2D-PIC simulations of firehose instability

Cited by in corpus (4)

• Modeling hot, anisotropic ion beams in the solar wind motivated by the Parker Solar Probe observations near perihelia
• Decoding the formation of hammerhead ion populations observed by Parker Solar Probe
• Hybrid simulations of the proton beam instabilities in the young solar wind. The formation of hammerhead-like distributions
• Nature of Transonic Sub-Alfvénic Turbulence and Density Fluctuations in the Near-Sun Solar Wind: Insights from Magnetohydrodynamic Simulations and Nearly-Incompressible Models